The present disclosure relates to a technical field regarding acoustic conversion devices, and specifically relates to a technical field for realizing improvement in acoustic properties by providing a reinforcing member to a gap formed between a diaphragm and a holding frame.
There is an acoustic conversion device which serves as a small speaker having an oscillator referred to as an armature which is integrated into various types of audio output devices such as headphones, earphones, hearing aids, and so forth.
With such an acoustic conversion device, a driving unit including an armature, and a diaphragm unit including a diaphragm are housed in a storage case having an audio output hole, vibration is propagated to the diaphragm by a beam portion when a vibration portion of the armature vibrates, and the propagated vibration is output as audio (e.g., see Japanese Unexamined Patent Application Publication No. 2007-74499).
The diaphragm unit includes a holding frame fixed to the driving unit, a resin film adhered to the holding frame in a state covering an opening of the holding frame, a diaphragm held on the inner side of the holding frame in a state adhered to the resin film, and a beam portion for propagating the vibration of the vibrating portion of the armature to the diaphragm. With the beam portion, both edge portions are combined with one edge portion of the diaphragm, and the vibrating portion of the armature, respectively.